1 . Field of the Invention
The present invention relates to a power generation system, in particular, a generation system based on a pressure differential.
2 . Description of Related Art
Increased fossil fuel costs, as well as a growing preference for renewable sources of energy, have led to considerable developments in the area of renewable power generation. While most of the focus has been on the traditional sources of renewable energy, e.g., wind power, solar power, tidal power, etc., other natural phenomena have also been utilized to provide alternative sources for power generation.
U.S. Pat. No. 4,157,014 in the name of Clark describes a differential pressure system for generating power. The system of Clark comprises a pair of connected vertical columns filled with a thermally expandable fluid. At the lower ends of the columns, a heat source is provided, while at the upper end of the columns, a heat sink is provided between the columns. As the heat source heats the fluid at the lower end of one of the columns, the fluid expands, and rises up the column. At the top of this column, the fluid passes through the heat sink, which acts to cool the fluid. The cooled fluid contracts, and this relatively dense fluid flows down the second column to the lower end, where it is again heated by the heat source.
This behavior results in a circular flow of fluid between the columns, with the height difference between the upper and lower ends of the columns acting to drive the fluid around in a circular loop. A power transfer system (e.g., a turbine) is provided between the upper ends of the columns and the motion of the fluid drives this power transfer system to generate power, which can be transmitted for external use. Such a system can be used, for example, in conjunction with a geothermal heat source, as a way to extract useful work from a natural phenomenon.
However, a problem with the system of Clark is that it operates with low efficiency. Once fluid passes through the power transfer system, it will flash to a vapor or steam. For the Clark system to operate successfully, this vapor must undergo a change of state back to the original fluid. Such a state change requires additional energy, and results in an energy loss in the system. Accordingly, the system as described in Clark suffers from a relatively low efficiency rating.